A neurosurgery patient treated at a New Hampshire hospital this spring did have a rare brain disorder known as Creutzfeldt-Jakob Disease, health officials confirmed Friday. That means that 15 other people in three states may have been exposed to the invariably deadly infection through potentially tainted surgical equipment.

Autopsy results came back positive for CJD from the National Prion Disease Pathology Surveillance Center and were reported to the New Hampshire Department of Health and Human Services and Catholic Medical Center, where the surgery took place.

Earlier this month, New Hampshire officials notified eight patients who may have been exposed to CJD through shared equipment. Five others in Massachusetts and two in Connecticut were also warned of the risk, health officials in those states said.

"Though we are not surprised by the test results, we are saddened by the toll this disease takes on families and our sympathies go out to all those affected," said Dr. Jose Montero, New Hampshire's director of public health, in a statement. There is no way to confirm the disease except through autopsy after a patient's death.

The initial patient turned out to have sporadic CJD, which occurs spontaneously. It's not the variant form of the disease that causes a human type of "mad cow disease" and is associated with eating beef contaminated with the cattle version of the infection, called bovine spongiform encephalopathy, or BSE, experts said.

The problem arose because standard hospital disinfection techniques cannot eradicate the prion that causes CJD. A prion is a protein and the type that causes BSE and CJD is misfolded and somehow manages to transform other proteins into disease-causing shape.

The initial patient had surgery at Catholic Medical Center in Manchester, N.H., where eight others were also treated. The five Massachusetts patients underwent surgery at Cape Cod Hospital in Hyannis, while the two Connecticut patients were treated at the Veterans Affairs Hospital in West Haven, health officials said.

The Massachusetts and Connecticut patients were all treated using a guided imaging navigation system manufactured by Medtronic Inc., as well as the surgical tools that go with it, a company spokeswoman said. Other patients were treated with tools made by different manufacturers. Hospitals frequently share high-cost neurosurgery equipment on a fee-for-use or rental basis, which explains why they were used in more than one hospital.

The risk of infection is very low, noted Dr. Joseph Pepe, president and CEO of Catholic Medical Center. The eight New Hampshire patients were notified Friday of the autopsy results.

This is not the first time contaminated hospital equipment has been implicated in potentially spreading CJD. In 2000, 14 patients in two separate incidents were exposed. The Joint Commission, an accrediting agency, this month reiterated guidelines urging hospitals to have a high degree of suspicion about CJD even when the diagnosis is not confirmed and to follow World Health Organization and Centers for Disease Control guidance on sterilization or disposal of the tools.

CJD affects about one in a million people worldwide each year, experts say. In the most recent five-year period, between 279 and 352 cases were diagnosed in the U.S. annually, according to the Centers for Disease Control and Prevention. Early symptoms include rapidly failing memory and other cognitive problems. Personality changes, anxiety, depression, lack of coordination and visual disturbances often occur. There is no treatment and no cure. officials said.

JoNel Aleccia is a senior health reporter at NBC News. Reach her on Twitter at @JoNel_Aleccia or send her an email.